The versatility and performance of newer muscle cars such as the FORD MUSTANG permit owners to use one vehicle for multiple purposes. Often the same vehicle used to carry groceries home from the supermarket is used for racing applications on the weekend. Owners will often modify their vehicle to make it more competitive in their chosen form of racing. One of the most modified areas of a vehicle for racing applications is the engines air induction system.
Tuning the air induction system can be one of the most critical aspects of getting a vehicle to produce horsepower and torque for either street or racing applications. The basic function of an air induction system is to provide an optimized and evenly distributed flow of fresh air from the air filter to the combustion chamber. The intake manifold is the primary component of the air induction system. In a fuel injected engine the intake manifold includes at least one air intake conduit for each cylinder. The air intake conduit generally extends between the throttle body and the intake port(s) leading to the combustion chamber. In addition to the mere routing of air, today's intake manifolds may also include dynamic supercharging, swirl and tumble control, positive crankcase ventilation and exhaust gas re-circulation.
Charge motion control valves (“CMCVs”) are often used within air induction systems in order to modify the flow of air and fuel into the engine's cylinders. A CMCV is typically and operatively disposed within an air intake conduit of the air induction system “upstream” from a fuel injector. The CMCV is effective to alter the flow of air into the cylinder during certain vehicle operating modes (e.g., during relatively low engine speed and load conditions), and is effective to create turbulence within the cylinder.
One type of CMCV is designed for use in combination with a “Siamese” type intake port which includes an air intake port that splits or “branches” into a pair of separate ports that communicate with one of the engine's cylinders. This type of CMCV is typically and operatively disposed in close proximity to the location where the air intake port splits and is designed to alter the flow of air into each of the port branches. These CMCVs are commonly referred to as “swirl” type CMCVs and are typically designed to substantially “cover” one side of the air intake port, thereby preventing air from entering one of the branches. In this manner, the CMCV provides a “fuel rich” mixture within the covered branch that is subsequently discharged into the cylinder and combusted. Additionally, this type of CMCV covers only a portion of the other side of the main air intake port, effective to allow a substantial amount of air to flow into the other branch and to create a “fuel lean” mixture in that branch that is subsequently discharged into the cylinder and combusted along with the fuel rich mixture. This flow of air into the cylinder creates a swirling effect or turbulence which causes the fuel rich mixture and fuel lean mixture to combine for combustion.
While these prior CMCVs provide emissions benefits, low RPM, and low load engine operation, they suffer some drawbacks which adversely effect the efficiency of the engine during certain operating conditions. For example and without limitation, during cold start operating conditions (i.e., when the vehicle is being started after being exposed to relatively cold temperatures), fuel often condenses on the intake valves due to a lack of heat. Because this type of prior CMCV substantially blocks air from flowing into one of the port branches, condensed fuel often remains on the intake valve within that branch and/or enters the cylinder as a liquid stream and is thus not properly combusted within the cylinder. This undesirably leads to oil degradation, waste fuel, and increased hydrocarbon emissions.
Another prior type of CMCV, commonly referred to as a “tumble” type CMCV, is used to create a “tumbling” flow of air into the cylinders. This type of CMCV provides substantially symmetrical passages for air to flow to each intake valve. Hence, this type of CMCV provides a substantially similar air/fuel mixture and airflow within each branch port. While this type of CMCV prevents condensation from remaining on the intake valves, it substantially restricts air flowing into the combustion chamber. The restriction of air limits the device to use at low engine RPMs and low engine torque requirements.
Another type of CMCV is used to create both tumble and swirl air flow into the cylinders. This type of CMCV provides more air to one intake branch than to the other. This construction prevents some fuel from condensing on the valve receiving the least amount of air and provides a swirl to the combustion chamber via the predominant air flow to the second branch. While this type of CMCV provides some advantages over the other types of CMCVs, because only 10% of the air being supplied to the cylinder is allowed to flow through one branch of the intake, condensed fuel often remains on the intake valve within that branch and/or enters the cylinder as a liquid stream and is thus not properly combusted within the cylinder. This undesirably leads to oil degradation, waste fuel, and increased hydrocarbon emissions.
In addition to the air restriction present in all of the CMCV constructions of the prior art, the devices add substantial complexity to an already complex air induction system. The CMCVs require a pivotally mounted butterfly type valve for each intake branch. The butterfly valves must be coordinated for uniform opening and closing in response to engine speed and torque demands. The coordination requires a combination of solenoids, stepper motors and/or vacuum motors. The motors must be in electrical communication with the on-board computer and a vast array of sensors to cause the CMCVs to open above a predetermined RPM or engine torque requirement to prevent fuel and air starvation. Starving of the engine from fuel and/or air could create dangerous driving situations, as the engine would not respond properly to operator throttle demands.
Accordingly, what is needed in the art is a charge motion plate for high-performance applications. The charge motion plate should achieve objectives such as: even distribution of the fuel and air mixture to both branches of a siamese intake port arrangement, reduced airflow restriction for crisper throttle response and increased horsepower, compatibility with original equipment manufacturer “OEM” or aftermarket turbo chargers and superchargers, and compatibility with nitrous oxide injection systems.
In addition, the charge motion plate should be easily manufactured without moving parts to malfunction or adjust. The charge motion plates should include packaging flexibility for installation on various vehicle configurations including retrofitting existing vehicles with minimal modification to the existing air induction system.